U.S. patent number 6,752,727 [Application Number 09/776,505] was granted by the patent office on 2004-06-22 for golf club head and method of manufacturing the same.
This patent grant is currently assigned to Yamaha Corporation. Invention is credited to Mutsumi Harada, Tatsuya Hirakawa, Hiroaki Inoue, Atsushi Uchida.
United States Patent |
6,752,727 |
Harada , et al. |
June 22, 2004 |
Golf club head and method of manufacturing the same
Abstract
By hot pressing a cold rolled .beta. type titanium alloy which
has not been subjected to solution heat treatment into a
predetermined shape, it is possible to obtain a part with a cold
rolled metallurgical texture in its approximately central portion
in the thickness direction, and a solution heat treatment
metallurgical texture in its other portions, and a golf club head
is manufactured using this part as a face member.
Inventors: |
Harada; Mutsumi (Hamamatsu,
JP), Inoue; Hiroaki (Hamamatsu, JP),
Uchida; Atsushi (Hamamatsu, JP), Hirakawa;
Tatsuya (Hamamatsu, JP) |
Assignee: |
Yamaha Corporation
(Shizuoka-ken, JP)
|
Family
ID: |
18557178 |
Appl.
No.: |
09/776,505 |
Filed: |
February 2, 2001 |
Foreign Application Priority Data
|
|
|
|
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Feb 3, 2000 [JP] |
|
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P2000-032602 |
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Current U.S.
Class: |
473/342; 473/345;
473/349 |
Current CPC
Class: |
A63B
60/00 (20151001); A63B 53/04 (20130101); A63B
2209/00 (20130101); A63B 53/0408 (20200801) |
Current International
Class: |
A63B
53/04 (20060101); A63B 053/04 () |
Field of
Search: |
;473/324,325,342,345,346,349,332,329,347,348 ;273/DIG.23
;148/669 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Passaniti; Sebastiano
Attorney, Agent or Firm: Dickstein, Shapiro, Morin &
Oshinsky, LLP.
Claims
What is claimed is:
1. A golf club head having a face member formed by hot pressing a
cold rolled .beta. type titanium alloy which has not been subjected
to solution heat treatment wherein the metallurgical texture of the
approximately central portion in the thickness direction of the
face member is a cold rolled metallurgical texture, and the other
portions have a solution heat treatment metallurgical texture.
2. A golf club head according to claim 1, wherein the hardness of
an approximately central portion in a thickness direction of the
face member is higher than the hardness of other portions.
3. A golf club head according to claim 2, wherein if the thickness
of the face member is T mm, the thickness of the approximately
central portion in the thickness direction is greater than or equal
to 0.05 T mm and less then or equal to 0.7 T mm.
4. The golf club head according to claim 1, wherein if the
thickness of the face member is T mm, the thickness of the
approximately central portion in the thickness direction is greater
than or equal to 0.05 T mm and less then or equal to 0.7 T mm.
5. The golf club head according to claim 4, wherein the head volume
is at least 250 cc.
6. The golf club head according to claim 3, wherein the head volume
is at least 250 cc.
7. The golf club head according to claim 2, wherein the head volume
is at least 250 cc.
8. The golf club head according to claim 1, wherein the head volume
is at least 250 cc.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a golf club head and a method of
manufacturing the same, and more specifically, it relates to a golf
club head which can provide high durability and an excellent feel
on striking the ball (the feeling on impact with the ball), and a
method of manufacturing the same.
This application is based on Patent Application No. 2000-32602,
filed in Japan, the contents of which are incorporated herein by
reference.
2. Description of the Related Art
Hitherto, golf club heads using face members made by pressing a
.beta. type titanium alloy which has been subjected to solution
heat treatment have been known.
However, in such prior art golf club heads, in terms of the
material properties, the face portion has elasticity, but does not
have sufficient strength, which is somewhat disadvantageous from
the viewpoint of durability.
Further, golf club heads provided with face members which are made
by cold pressing a cold rolled .beta. type titanium alloy which has
not been subjected to solution heat treatment are also known.
Compared to the above-mentioned golf club heads which are provided
with face members which have been subjected to solution heat
treatment, the face portions of these golf club heads have higher
strength, but since they are not solution heat treated, there is a
large amount of residual stress in the interior of the metal, and
because their elasticity is also small, there are the disadvantages
that the face portion is easily cracked, the feel on striking the
ball is stiff, and a good feel on striking the ball cannot be
obtained.
The present invention was made in order to overcome these
disadvantages, and it is an object of the present invention to
provide a golf club head with increased strength and at the same
time, improved durability, and which can further provide a good
feel on striking the ball.
SUMMARY OF THE INVENTION
In order to achieve the above goals, the present invention employs
a method wherein parts formed into a predetermined shape by hot
pressing a cold rolled .beta. type titanium alloy which has not
been subjected to solution heat treatment are used for at least the
face member. As a result of using this method, it is possible to
obtain approximately the same degree of strength as for a golf club
head made of a cold pressed .beta. type titanium alloy which has
not been subjected to solution heat treatment, with a surface which
does not easily crack, with greatly improved durability, and which
also has a mild feel on striking the ball.
According to the present invention, the durability, of the face
member is increased, and therefore, it becomes possible to make the
face member thinner. When making the face member thinner, the
remaining weight can be placed around the periphery or on the sole
of the head, and the head can be designed so that the moment of
inertia can be increased, and/or the center of gravity can be made
lower and/or deeper, and as a result of these effects, further
increases in the flight distance and the directional stability can
be expected.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically illustrates the structure of a cross section
of the metal of an embodiment of the present invention.
FIG. 2 schematically illustrates the structure of a cross section
of the metal of a comparative example.
FIG. 3 schematically illustrates the structure of a cross section
of the metal of a comparative example.
FIG. 4 illustrates a wood including the metal of an embodiment of
the present invention.
FIG. 5 illustrates an iron including a metal of an embodiment of
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the golf club head of the present invention, at least one part
of the face portion is a face member formed into a predetermined
shape by hot pressing a cold rolled .beta. type titanium alloy
which has not been subjected to solution heat treatment. The face
according to the present invention is preferably used for a wood
type golf club (FIG. 4), however, the face may also be used for an
iron type golf club (FIG. 5).
The face member formed in this way has a sandwich type constitution
in which its approximately central portion in the thickness
direction has a metallurgical texture corresponding to a cold
rolled metallurgical texture, and the other portions have a
solution heat treatment metallurgical texture (a granular
metallurgical texture). The portion composed of the cold rolled
metallurgical texture (the approximately central portion in the
thickness direction) has a higher hardness than the other portions
which have a solution heat treatment metallurgical texture
(granular metallurgical texture).
Further, in the present specification, "in the thickness direction"
of the face member is used to indicate the direction from the front
surface side to the back surface side of the face member.
If the thickness of the above-mentioned face member of the present
invention is T mm, it is preferable that the thickness of the above
mentioned approximately central portion in the thickness direction
is designed to be equal to or greater than 0.05 T mm and less than
or equal to 0.7 T mm. Further, it is effective to apply the golf
club head of the present invention to No. 1 Woods with a head
volume of 250 cc or greater.
The manufacture of the golf club head of the present invention can
use a method in which, after forming a cold rolled .beta. type
titanium alloy which has not been subjected to solution heat
treatment into parts of a predetermined shape by hot pressing,
under heating conditions of a maximum temperature of 800.degree. C.
to 1100.degree. C., with a heat application time of 4 sec to 14
sec, these parts are used for at least the face member.
EXAMPLES
Examples of the golf head of the present invention will be
explained below, in comparison with comparative examples.
Example 1
2.6 mm thick plate of a cold rolled material of a .beta. type
titanium alloy which had not been subjected to solution heat
treatment was subjected to heat treatment under the same conditions
as for hot pressing. That is, a cold rolled material which was not
subjected to solution heat treatment was heated to a maximum
temperature of 900.degree. C. for 10 sec by high frequency heating.
After this heat treatment, an aging treatment was carried out at
500.degree. C. for 5 hours to make a sheet of material for golf
club heads. Then, from the obtained sheet of material, three
tensile test specimens (JIS 13B, 1/2 size) were cut out, and
tensile testing was carried out on these tensile test specimens at
a fixed speed of 1 mm/min. The results of this test are shown in
Table 1. The tensile strength Ts was 1320 N/mm.sup.2, the yield
strength Ys was 1232 N/mm.sup.2, and the elasticity E1 was
5.5%.
Further, to observe the metallurgical texture, from the above sheet
of material, heat treatment sample articles were made, and were
sectioned along the thickness direction. Then, after covering the
sectioned surface of the samples in a predetermined resin, and
polishing, the surfaces of the sectioned faces were etched in a 3%
solution of hydrofluoric acid, and the metallurgical texture was
observed. As a result, as shown in FIG. 1, in the central portion
in the thickness direction, a cold rolled metallurgical texture 11
(linear metallurgical texture) for compression in the thickness
direction can be seen. Further, at either side in the thickness
direction, a solution heat treatment metallurgical texture 12
(granular metallurgical texture) can be seen. That is, the sheet of
material of the present example has a sandwich constitution in
which the approximately central portion in the thickness direction
and the other portions differ in their metallurgical textures, and
when the hardnesses of these portions is studied, it is found that
the above-mentioned central portion has a higher hardness than the
other portions.
Manufacturing Example 1
The same cold rolled .beta. type titanium alloy material of Example
1 was hot pressed, and a face member was formed, and using the
same, a 250 cc golf club head was manufactured. The hot press
heating conditions were a maximum temperature of 900.degree. C.
with a heat application time of 10 sec. After the welding process,
aging was carried out at 500.degree. C. for 5 hours, and polishing
was carried out to obtain a golf club head. A shaft and a grip were
attached to the golf club head obtained in this way, to manufacture
a golf club head known as a No. 1 Wood (driver). Using this golf
club, the inventor of the present invention, using a continuous
impact testing apparatus he developed, tested the durability of the
golf club according to the present Manufacturing Example 1, and
found that even after 10000 impacts, there were no cracks at all
visible on the surface of the face. Further, an assessment of the
feel on striking the ball of this golf club was carried out using a
group of 28 golfers with handicaps from 5 to 16. The assessment was
carried out by having each of the golfers select the golf club with
the best feel on striking the ball, from among three golf clubs,
including the golf clubs according to the Comparative Manufacturing
Examples 1 and 2 described later. The result was that 23 of the 28
golfers chose the club according to the present Manufacturing
Example 1. Further, as shown in FIG. 1, in the face member of this
golf club head, the hardness of the approximately central portion
in the thickness direction is higher than the hardness of the other
portions, moreover, the metallurgical texture has a sandwich
constitution in which the approximately central portion in the
thickness direction has a cold rolled metallurgical texture 11, and
the other portions have a solution heat treatment metallurgical
texture 12.
Further, using the same heat pressing conditions of the .beta. type
titanium alloy of Manufacturing Example 1, except that the maximum
temperature was varied from 800.degree. C. to 1100.degree. C., and
the heating time was varied from 4 to 14 sec, face members were
made in the same way as in Manufacturing Example 1. Golf clubs were
manufactured using these face members, and it was found that when
the heating conditions are within the above ranges, results
approximately equal to those of Manufacturing Example 1 are
obtained.
Comparative Example 1
The same cold rolled .beta. type titanium alloy of Example 1, after
solution heat treatment at 830.degree. C. for 5 min, and after
being subjected to high frequency heating to a maximum temperature
of 1000.degree. C. for 12 sec, was aged under the same conditions
as in Example 1, and was made into a sheet of material for golf
club heads. Then, tensile strength testing of this sheet of
material was carried out by the same method as in Example 1, and as
shown in Table 1, the tensile strength Ts was 1125 N/mm.sup.2, the
yield strength Ys was 1050 N/mm.sup.2, and the elasticity E1 was
6.0%. Further, the metallurgical texture was observed in the same
way as for Example 1, and as shown in FIG. 2, a solution heat
treatment metallurgical texture 12 (granular metallurgical texture)
was observed throughout the sample.
Comparative Manufacturing Example 1
The same cold rolled .beta. type titanium alloy material as that of
Comparative Example 1, after being subjected to the same solution
heat treatment as in Comparative Example 1, was formed into a face
member by hot pressing, and was used to manufacture a golf club
head in the same way as the above Manufacturing Example 1. The
heating conditions of the solution heat treatment were a maximum
temperature of 830.degree. C. for 5 min, and the heating conditions
of the hot pressing were a maximum temperature of 1000.degree. C.,
and a heat application time of 12 sec. After the welding process, a
golf club was obtained by the same process as in the above
Manufacturing Example 1. Using the obtained golf club, assessments
of the durability and the feel on striking the ball were carried
out by the same methods as in the above Manufacturing Example 1. As
a result, as shown in Table 1, cracking occurred in the central
portion of the face surface after 7523 impacts. Further, among the
golf clubs of the above Manufacturing Example 1, the present
Comparative Manufacturing Example 1, and the following Comparative
Manufacturing Example 2, only 4 out of 28 golfers chose the golf
club according to the present Comparative Manufacturing Example 1
as the golf club with the best feel on hitting the ball.
Comparative Example 2
The same cold rolled .beta. type titanium alloy material of Example
1 was subjected only to an aging treatment under the same
conditions as those of Example 1, and a sheet of golf club head
material was made. Then, tensile strength testing of this sheet of
material was carried out by the same method as in Example 1, and as
shown in Table 1, the tensile strength Ts was 1405 N/mm.sup.2, the
yield strength Ys was 1380 N/mm.sup.2, and the elasticity E1 was
0.9%. Further, the metallurgical texture was observed in the same
way as for Example 1, and as shown in FIG. 3, a cold rolled
metallurgical texture 11 (linear metallurgical texture) was
observed throughout the sample.
Comparative Manufacturing Example 2
A process approximately the same as that used in the formation of
the sheet of material in the above Comparative Example 2 was
followed, and a face member was formed from a cold rolled .beta.
type titanium alloy material, and a 250 cc golf club head was
manufactured using this face member. That is, after cold pressing
the above mentioned cold rolled material, a golf club head was
obtained by carrying out the same process as in the above Example
1. Then, using a golf club provided with this golf club head,
assessments of the durability and feel on striking the ball were
carried out using the same methods as in the above Example 1, and
as shown in Table 1, cracking occurred in the central portion of
the, face surface after 2505 impacts. Further, only 1 out of 28
golfers felt that the golf club according to the present
Comparative Manufacturing Example 2 had a good feel on striking the
ball.
TABLE 1 Comparative Comparative Example 1 Ex. 1 Ex. 2 Solution Heat
Treatment No Yes No Heat Yes/No Yes Yes No Treatment Temp (.degree.
C.) 900 1000 -- Tensile Strength (N/mm.sup.2) 1320 1125 1405 Yield
Strength (N/mm.sup.2) 1232 1050 1380 Elongation E1 (%) 5.5 6.0 0.9
Metallurgical Cross FIG. 1 FIG. 2 FIG. 3 Sectional Texture
Durability (Impacts) 10000 7523 2505 Feel on Striking Ball 23 4
1
From these results, as shown in Table 1, it can be understood that
the face member of the golf club head according to Manufacturing
Example 1 has a tensile strength Ts and a yield strength Ys close
to that of the face member made by cold pressing (Comparative
Manufacturing Example 2), but its elasticity E1 is close to that of
the face member made by hot pressing (Comparative Manufacturing
Example 1). Further, the metallurgical texture of the face member,
as shown in FIG. 1, is formed in a sandwich constitution having a
cold rolled metallurgical texture 11 in the approximately central
portion in the thickness direction of the face member, and a
solution heat treatment metallurgical texture (granular
metallurgical texture) in the other portions. As shown in Table 1,
it can be recognized that this leads to the effects that the golf
club of the present Example 1 has a higher durability and a better
feel on striking the ball than the golf club heads according to
Comparative Examples 1 and 2.
Although the invention has been described in detail herein with
reference to its preferred embodiments and certain described
alternatives, it is to be understood that this description is by
way of example only, and it is not to be construed in a limiting
sense. It is further understood that numerous changes in the
details of the embodiments of the invention, and additional
embodiments of the invention, will be apparent to, and may be made
by, persons of ordinary skill in the art having reference to this
description. It is contemplated that all such changes and
additional embodiments are within the spirit and true scope of the
invention as claimed.
* * * * *